During the past 25 years, a number of important innovations have been made in the diagnosis of urinary stress incontinence. Whereas, in the past, the emphasis was upon surgical approaches to problems in this area, such thinking has, with advances in the field, undergone substantial change.
It is now important to evaluate the patient preoperatively, with an objective investigation, to determine the degree of anatomic abnormality present so that an appropriate choice of surgical approach can be made at the outset.
The introduction of the chain cystourethrogram has proved to be an important diagnostic aid in the evaluation of patients with urinary stress incontinence. With this technique, the posterior urethrovesical angle and the urethral axis can be investigated easily, and a rational method of operative repair selected for each patient.
Green, in 1963, identified two basic anatomic defects as causing stress incontinence. In type I, the posterior urethrovesical angle is lost, but the inclination of the urethral axis is maintained at at least a 45.degree. angle to the vertical. Symptomatology in patients with type I defects ranges from mild to moderate incontinence and is managed by restoring the posterior urethrovesical angle by anterior colporrhaphy. In a type II deformity, not only is the posterior urethrovesical angle lost, but the urethral axis is rotated posteriorly past 45.degree. to the vertical. This rotation of the urethral axis can be demonstrated quite accurately in a chain cystourethrogram. Patients having type II stress incontinence often exhibit severe symptoms and usually require a retropubic urethropexy rather than an anterior colporrhaphy to effect a cure.
In 1971, Crystle et al reported the "Q-tip test" as a simple means of differentiating between type I and type II defects: When a cotton-tipped applicator is inserted into the bladder neck, the patient is asked to strain, the free end of the applicator stick develops an arc directly opposite to the arc formed by the end of the stick within the urethra. The degree of rotation of the stick's free end was found to correlate well with the degree of the axis rotation of the urethra, as observed on the chain cystourethrogram. Similar results have been reported by Reynolds and Miller.
In the above approach, a significant degree of guesswork was necessitated in attempting to estimate the degree of axis rotation formed by the end of the cotton-tipped applicator.
The present invention represents a response to the needs which were evidenced by the shortcomings in the above-described prior art efforts.